1. Field of the Invention
This invention relates generally to refuse collection vehicles and more specifically to means for detecting the presence of personnel in proximity to dangerous loading apparatus associated with the vehicles.
2. Description of the Prior Art
Refuse collection vehicles have been provided with various designs to accommodate the unloading of individual refuse containers into the vehicle by refuse collection personnel. Generally, the vehicles have been provided with a small hopper into which the personnel have initially loaded the refuse. When the hopper has become full, loading apparatus has been actuated to move the refuse from the hopper into a large storage body.
In a first type of vehicle, hydraulically actuated packing panels have scooped the refuse from the hopper and packed it into the storage body in a manner such as that disclosed and claimed in my copending application Ser. No. 264,021, now U.S. Pat. No. 3,899,091, assigned of record to the assignee of record of the present application. In this type of apparatus the hopper, which is typically provided at the rear of the vehicle, is partially defined by a loading lip over which the individual containers are emptied by the personnel. From a normally tucked position above the hopper, a hydraulically actuated packing panel moves so that a narrowed edge thereof passes in close proximity to the loading lip. This type of loading operation is particularly desirable since the packing panel and the loading lip function as a pair of jaws as they move into relative proximity with each other. This movement can be of advantage in chopping large objects into a more convenient size; however, it can also be particularly dangerous to personnel. Anyone having an arm or leg extending over the loading lip could be severly injured during the loading operation.
To compound the danger, this loading operation is performed in closest proximity to the area around which the personnel normally operate. Furthermore, refuse which has not been fully loaded into the hopper often extends over the loading lip, and there is some tendency for the personnel to push this refuse into the path of the packing panel. This, of course, increases the probability of injury.
In a second type of vehicle, the hopper is typically supported by a pair of arms in a normal position at the front of the vehicle. The arms are pivotally mounted to the vehicle to raise and overturn the hopper so that its contents empty into the storage body. This type of loading apparatus is particularly dangerous to anyone who might have moved into the normal position of the hopper. Such a person could be struck and severly injured by the hopper during the loading operation.
In both of these types of vehicles, the loading apparatus generally includes an electrical circuit for selectively energizing a motor which in turn rotates a pump to provide a source of pressurized fluid. This fluid is typically used to operate the hydraulic cylinders associated with the packing panel in the first type of vehicle and the loading arms in the second type of vehicle.
To reduce the obvious danger to personnel, the electrical circuits in these types of loading apparatus have been provided with a plurality of switches, biased in a normally open position, which have had to be simultaneously closed to perform the loading operation. The switches have been mounted at positions spaced from the dangerous area and have been widely separated so that they have not been simultaneously actuable by a single person. This system has worked well where the number of loading personnel has equaled the number of switches. However, where the number of personnel has exceeded the number of switches, the excess personnel have been free to move into the dangerous area. Where the number of loading personnel has been less than the number of switches, the driver of the vehicle has typically had to participate in the loading operation.